Optimization and evaluation of microencapsulated artificial diet for mass rearing the predatory ladybird Propylea japonica (Coleoptera: Coccinellidae)

Abstract

Artificial diet optimization is a key aspect in mass rearing of natural enemies since it influences the quality and feeding effectiveness, and thus the success of the biological control program. Here, we introduced the microencapsulation method to package liquid artificial diet for feeding of the ladybird Propylea japonica. An orthogonal test of the quality of microencapsulated artificial diets (ADMs) was performed on key variables in production; Ca-alginate concentration, chitosan concentration and weight ratio of wall material to inner diet. We compared the development and reproduction of P. japonica fed on the ADMs under different cold-stored periods with those fed on fresh aphids and liquid artificial diets, in addition to a comparison of respiration, locomotion and predation. Our results indicated that chitosan concentration and ratio of shell to core significantly influence the quality of ADMs. The optimal recipe is 1.0% Ca-alginate, 1.6% chitosan and shell : core = 1 : 2. Insects reared on fresh optimized ADMs were similar to those fed on fresh prey in all developmental and reproductive characteristics except for survival ratio and female fertility. ADMs appeared more beneficial than using a liquid artificial diet, although this may decrease with the prolonging of the cold-storage period. P. japonica fed either on fresh ADMs or fresh prey showed improved respiration and predation abilities compared to where liquid artificial diet was used. Our study indicates advantages of microencapsulation in the production of artificial diet for predatory ladybird rearing. A microencapsulated diet can directly increase the efficiency and stability of mass rearing.

Reproductive performance of Propylea japonica (Coleoptera: Coccinellidae) under various light intensities, wavelengths and photoperiods

“…To maximize reproductive success, beetles should be housed in cages under an overhead light source generating 1500 lux of white light in a 18L : 6D photoperiod. Although P. japonica can be conveniently reared on encapsulated artificial diet (Tan et al, 2014), this denies the insects plant material and thus any beneficial effects of exposure to reflected green light. We hypothesize that improved reproductive performance might be obtained with reusable artificial leaves, cut from thin sheets of green plastic film clipped to vertical supports in a horizontal orientation to serve as oviposition substrates.…”

“…It is widely released in greenhouse cultures because of its tolerance of high temperature, low humidity conditions (Kawauchi, 1983) and the suitability of various whitefly and aphid species for its development and reproduction (Chi & Yang, 2003;Zhang et al, 2007). Techniques for mass rearing P. japonica on artificial diet have been developed (Tan et al, 2014) and although suitable thermal conditions are well defined, the ideal light conditions and regimes for mating behavior, oviposition rate, and egg fertility have not yet been explored and were therefore the focus of this study. To this end, we employed LED illuminators under temperature-controlled conditions to manipulate light photoperiod, wavelength and intensity and continuously monitored P. japonica mating behavior under both light and dark conditions using digital video recording equipment and an infrared, night-vision camera (Noldus et al, 2002).…”

“…The beetles were confined in a plastic frame cage (45.0 × 45.0 × 50.0 cm) covered with mesh fabric and provisioned daily with 100 microcapsules of an artificial diet previously demonstrated to be suitable food for successful development and reproduction in this species (Tan et al, 2014). Several young seedlings of broad bean, Vicia faba (5 leaf stage) were also placed in the cage and refreshed every two days.…”

Preparation of Microcapsules Containing Artificial Diet for Tropical Fishes with Spray Gelling Method

“…The main purpose of these microcapsules was to microencapsulate a few balanced nutritious baits in accordance with the conditions of fishes [8] [9] [10].…”

An artificial diet containing plant pollen for the mealybug predator Cryptolaemus montrouzieri

“…In 2009, Riddick reviewed the use of artificial diets for the rearing of various predaceous ladybirds. More recently, a microencapsulated artificial diet was developed for the predatory ladybird, Propylea japonica (Thunberg), with potential for use in its mass production …”